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Unformatted text preview: Introduction
Introduction to
Geoprocessing
Geoprocessing
With ArcGIS 9 What Is Geoprocessing?
Definition
Definition
A GIS operation used to manipulate GIS
GIS
data.
The application of a clearly defined operation that
creates new spatial data from existing or derived
data. In
In other words…
It
It allows us to ask questions of our GIS
database that cannot be answered by the
RAW data. Common
Common Geoprocessing Tasks
Data
Data Conversion
Shapefile
Shapefile to Geodatabase Feature Class Overlay
Overlay Operations
Union and/or Intersection Data
Data Extraction
Defining
Defining a subset through Clipping or Filter Proximity
Proximity Analysis
Buffering
Buffering Site
Site Selection
Employ
Employ Various ArcGIS Extensions ArcGIS Geoprocessing
ArcGIS
ArcGIS Implements Geoprocessing
Through The Use Of Toolboxes
Accessed from:
Accessed from:
ArcToolbox,
ArcCatalog Tree, or
Geodatabase ArcToolbox
Tools
Tools are typically
accessed through
ArcToolbox
A dockable window
dockable
with toolboxes
Since ArcGIS 9, the User
may dock in ArcCatalog,
ArcMap, ArcScene and
ArcGlobe ArcToolbox
ArcToolbox
ArcToolbox
ArcToolbox Tabs
Favorites
Favorites
list of toolboxes available to
use for current session
use for current session
user can add/remove toolbox Index:
Index:
Search tools alphabetically Search:
Search:
Search tools by keyword Supported Data Types
ArcGIS
ArcGIS 8.x,
ArcToolbox
ArcToolbox worked primarily with
Coverages
Shapefiles/Feature
Shapefiles/Feature Classes employed the
Geoprocessing Wizard; very limited! ArcGIS
ArcGIS 9
It
It is claimed ArcToolbox can work with all
data types used in ArcGIS, even layers! ArcGIS Geoprocessing
Toolboxes
Toolboxes contain
Toolsets and Tools
Tools
Tools
Requires interaction from
user prior to functioning System
System Tools
Pre-Loaded, written by
ESRI
Read-Only Custom
Custom Tools
Produced by the User System
System Tools
Core
Core Toolsets
Analysis
Analysis
Geoprocessing for Feature Classes Cartography
Cartography
Conversion
Conversion
Data
Data management
Geocoding
Geocoding
Linear
Linear Referencing
Spatial
Spatial Statistics
Coverage
Coverage
Geoprocessing for Coverages
ArcInfo workstation installation only Number of tools
•ArcView: 102
•ArcEditor: 104
•ArcInfo: 251
•Spatial Analyst: 158
•3D Analyst: 45
•Geostatistical Analyst: 1 ArcGIS Geoprocessing
Tools
Tools May Be Run:
Via
Via their dialog box,
At the command
At the command
line,
line,
Within
Within a script or a
model. Running
Running tools via dialog box
Find
Find the tool from toolbox. Double click to activate
Dialog
Dialog boxes guide you through the process of
running a tool
Lets
Lets you specify the source data and other parameters Great
Great for
beginners
Help
Help readily
available Messages
Messages appear in progress dialogs Running
Running tools at the Command Line
The
The command line is similar to the ArcInfo Workstation
command line (but for ArcInfo/ArcEditor/ArcView)
You
You type a tool name, set appropriate parameter values, then
press Enter to execute the tool. Quicker if you
Quicker if you
know
know what
you’re doing
Less
Less Intuitive Usage
Usage of the tool is shown as you type Build and Run a Model
For
For geoprocessing involving multiple tools
Create
Create a new model by linking the tools together in a
graphical environment Documentation
Documentation
of
of model
process
Easily
Easily change
parameters and
rere-execute
model Models
A model contains one or
model
more processes
A process contains a tool
process
element and its parameter
values
values.
Tool
Tool
Project
Project data
data exists before the model
is run Derived
Derived data
output data created by a tool Input
Input value and derived
value
non-geographic values as
input or output Building
Building the Model
Drag
Drag and drop data and tools from ArcCatalog or ArcMap
Link
Link data and tools using connector
Set
Set input/output data and tool parameters (right
click/open) Building the Model
Expose
Expose input/output data or tool parameters to
dialog forms
Input/Output
Input/Output Data
right click> model parameter Tool
Tool
right click> make variable> from parameter
click> make variable> from parameter
right click> create parameter Running the Model
Three
Three states of a
model
Not
Not ready to run:
parameters not defined;
white background
hit Ready
Ready to run
colored Already
Already run
colored and shadowed A model is run in
model
either Model builder
or Toolbox. Create
Create and Run a Script
To
To automate geoprocessing tasks with scripts
written in COM-compliant scripting language to
COMexecute ArcGIS geoprocessing tools
Python, VBScript, Jscript, Perl
Python, VBScript, Jscript, Perl
# Import system modules
import sys, string, os, win32com.client
gp = win32com.client.Dispatch
("esriGeoprocessing.GpDispatch.1")
...
gp.workspace = “c:\\GISI”
Fcs = gp.ListFeatureClasses(“*“, “all“)
Clipfc = “c:\\GISI\\FL_boundary.shp”
Outworkspace = “c:\\GISI\\results”
fc = fcs.next()
while fc:
outname = outworkspace + "\\" + fc
gp.Clip_analysis (fc, clipfc, outname)
fc = fcs.next() Batch
Batch processing
Branching
Branching based
on conditions
Delayed
Delayed
processing
Can
Can run in
Toolbox or
outside ArcGIS ...
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